I second the request for a tutorial sir! This would awesome to have in my repituar.
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Thanks for the encouragement, my forge works well but if I built again I would change a few things.
I would not weld the burner to the shell (I would have a mount so I could move around the burner and let a little air in between the burner and the shell) and I would use a lighter gauge metal for the outside shell. There are a lot of how to build forge tutorials all over the web, I am not going to reinvent the wheel by doing another one. I built my forge with a mish mash of ideas from the net and what I remembered of the small forge that was in Mike Blues shop. Thanks to some advice from Mike at the MO meet my forge is working better. I ended up opening up the air-intake holes and putting on a choke tube on the outside of the burner. I also removed the regulator and am running straight off of tank pressure (This made a great deal of difference in the way the forge works).
There are some things I really like about this forge, I like the size of interior chamber, about 4” round by 11” works well for me while forging razors. I think around a 6 – 8 shell is about right. I also like the large front porch and the steel lining that reinforces the openings. I am also happy with the way the flame comes in tangent to the interior chamber and swirls around the heat seems pretty well distributed.
I have bought ceramic wool and satenite clay from High Temperature Tools & Refractory
I used these two links for ideas to rig together my burner A simple homemade propane burner Gas burners for forges, furnaces ... - Google Books
I had a small hole .025 (if I remember right) drilled in a 1/8 brass pipe cap for the jet, recently I changed that out for a mig tip (about the same size hole). The mig tip seems to be working a little better.
This is the second forge that I have made, I am definitely not an expert just a stubborn tinkerer. I have read a lot about forges on the British Blades Forums.
Charlie
Thank you for the additional information...but do you think you could show a few more pics showing all of the sides? I've got a good visual on the body of the forge, but am hung up on the burner end. What size of mig tip did you use? The size is usually stamped on them (I have a few around since I have a mig myself). On the ends of your forge, is the back solid or does it have a hole in it? My thoughts were to build mine like yours, but have bolt on ends to be able to rebuild the wool and mud.
OK, Charlie, so how's it on heating horseshoes? :hmmm:
:nj
Here are some more pictures. The tip is a .023. The front is bolted on the back is welded on.
Charlie
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I thank you so much Charlie. One last question and I'll leave you be for a little while...do you use any sort of regulator from the propane bottle? I have read a bit and have heard reference to regulating with a low pressure regulator like an acetylene regulator to get the fuel pressure right for the proper btu/heat...or is the torch shutoff you are using working fine for you?
Again thank you for your assistance. I think I'll plan on bolting both ends to repack easily, but pretty much a carbon of yours.
The pressure is straight from the tank no regulator, I regulate the flow with the needle valve the pressure is from the tank.
Charlie
This style of venturi burner works better with a lot of pressure behind the orifice. The high speed gas jet entrains air via vacuum as it is sent down the pipe. Internal turbulence will mix the air/gas and the magic happens at the burner end. Getting the right balance of air and gas has been calculated. Ron Reil was one of the first to publish a good deal of it. The balance is achieved by orifice size against the size of the air holes against the diameter and length of the tube. If you make the air holes too big, a choke tube is handy.
MIG tips are useful as they are already threaded, but the size of the orifice can be a little off. They might be designed for an 0.035 wire which means they may be 0.040 to allow the wire to pass through without dragging. I drill all mine. Even so, if you are observant and realize you may have a little more gas than you want, you adjust the air intakes and off you go. I'd recommend starting small and working up though.
The rest of the business of running one of these is no different than tuning a wind instrument. ;)
I have been doing some research on building my own forge. Running straight from the tank sounds like a great money saving idea beside the fact that it works better. I am wondering about the safety factor in doing this. Like Charlie's valve is hooked up with a hose clamp. That kinda scares me. He is still around so I assume it has worked so far but I think I would use a little more secure fitting and I am wondering if there are any other concerns like hose pressure etc. I may be wrong but I understand the propane tank pressure can be as high as 250psi.